/*
- * Copyright (C) 2009 Pierre-Marc Fournier
- * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * SPDX-License-Identifier: LGPL-2.1-or-later
*
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ * Copyright (C) 2009 Pierre-Marc Fournier
+ * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
*/
-#define _GNU_SOURCE
-#include <dlfcn.h>
+/*
+ * Do _not_ define _LGPL_SOURCE because we don't want to create a
+ * circular dependency loop between this malloc wrapper, liburcu and
+ * libc.
+ */
+#include <lttng/ust-dlfcn.h>
#include <sys/types.h>
#include <stdio.h>
+#include <assert.h>
#include <urcu/system.h>
#include <urcu/uatomic.h>
+#include <urcu/compiler.h>
+#include <urcu/tls-compat.h>
+#include <urcu/arch.h>
+#include <lttng/align.h>
+#include <helper.h>
#define TRACEPOINT_DEFINE
#define TRACEPOINT_CREATE_PROBES
+#define TP_IP_PARAM ip
#include "ust_libc.h"
#define STATIC_CALLOC_LEN 4096
static char static_calloc_buf[STATIC_CALLOC_LEN];
static unsigned long static_calloc_buf_offset;
-static void *static_calloc(size_t nmemb, size_t size)
+struct alloc_functions {
+ void *(*calloc)(size_t nmemb, size_t size);
+ void *(*malloc)(size_t size);
+ void (*free)(void *ptr);
+ void *(*realloc)(void *ptr, size_t size);
+ void *(*memalign)(size_t alignment, size_t size);
+ int (*posix_memalign)(void **memptr, size_t alignment, size_t size);
+};
+
+static
+struct alloc_functions cur_alloc;
+
+/*
+ * Make sure our own use of the LTS compat layer will not cause infinite
+ * recursion by calling calloc.
+ */
+
+static
+void *static_calloc(size_t nmemb, size_t size);
+
+/*
+ * pthread mutex replacement for URCU tls compat layer.
+ */
+static int ust_malloc_lock;
+
+static __attribute__((unused))
+void ust_malloc_spin_lock(pthread_mutex_t *lock)
{
- unsigned long prev_offset, new_offset, res_offset;
+ /*
+ * The memory barrier within cmpxchg takes care of ordering
+ * memory accesses with respect to the start of the critical
+ * section.
+ */
+ while (uatomic_cmpxchg(&ust_malloc_lock, 0, 1) != 0)
+ caa_cpu_relax();
+}
+
+static __attribute__((unused))
+void ust_malloc_spin_unlock(pthread_mutex_t *lock)
+{
+ /*
+ * Ensure memory accesses within the critical section do not
+ * leak outside.
+ */
+ cmm_smp_mb();
+ uatomic_set(&ust_malloc_lock, 0);
+}
+
+#define calloc static_calloc
+#define pthread_mutex_lock ust_malloc_spin_lock
+#define pthread_mutex_unlock ust_malloc_spin_unlock
+static DEFINE_URCU_TLS(int, malloc_nesting);
+#undef pthread_mutex_unlock
+#undef pthread_mutex_lock
+#undef calloc
+
+/*
+ * Static allocator to use when initially executing dlsym(). It keeps a
+ * size_t value of each object size prior to the object.
+ */
+static
+void *static_calloc_aligned(size_t nmemb, size_t size, size_t alignment)
+{
+ size_t prev_offset, new_offset, res_offset, aligned_offset;
+
+ if (nmemb * size == 0) {
+ return NULL;
+ }
/*
* Protect static_calloc_buf_offset from concurrent updates
res_offset = CMM_LOAD_SHARED(static_calloc_buf_offset);
do {
prev_offset = res_offset;
- if (nmemb * size > sizeof(static_calloc_buf) - prev_offset) {
- return NULL;
+ aligned_offset = LTTNG_UST_ALIGN(prev_offset + sizeof(size_t), alignment);
+ new_offset = aligned_offset + nmemb * size;
+ if (new_offset > sizeof(static_calloc_buf)) {
+ abort();
}
- new_offset = prev_offset + nmemb * size;
} while ((res_offset = uatomic_cmpxchg(&static_calloc_buf_offset,
prev_offset, new_offset)) != prev_offset);
- return &static_calloc_buf[prev_offset];
+ *(size_t *) &static_calloc_buf[aligned_offset - sizeof(size_t)] = size;
+ return &static_calloc_buf[aligned_offset];
+}
+
+static
+void *static_calloc(size_t nmemb, size_t size)
+{
+ void *retval;
+
+ retval = static_calloc_aligned(nmemb, size, 1);
+ return retval;
+}
+
+static
+void *static_malloc(size_t size)
+{
+ void *retval;
+
+ retval = static_calloc_aligned(1, size, 1);
+ return retval;
+}
+
+static
+void static_free(void *ptr)
+{
+ /* no-op. */
+}
+
+static
+void *static_realloc(void *ptr, size_t size)
+{
+ size_t *old_size = NULL;
+ void *retval;
+
+ if (size == 0) {
+ retval = NULL;
+ goto end;
+ }
+
+ if (ptr) {
+ old_size = (size_t *) ptr - 1;
+ if (size <= *old_size) {
+ /* We can re-use the old entry. */
+ *old_size = size;
+ retval = ptr;
+ goto end;
+ }
+ }
+ /* We need to expand. Don't free previous memory location. */
+ retval = static_calloc_aligned(1, size, 1);
+ assert(retval);
+ if (ptr)
+ memcpy(retval, ptr, *old_size);
+end:
+ return retval;
+}
+
+static
+void *static_memalign(size_t alignment, size_t size)
+{
+ void *retval;
+
+ retval = static_calloc_aligned(1, size, alignment);
+ return retval;
+}
+
+static
+int static_posix_memalign(void **memptr, size_t alignment, size_t size)
+{
+ void *ptr;
+
+ /* Check for power of 2, larger than void *. */
+ if (alignment & (alignment - 1)
+ || alignment < sizeof(void *)
+ || alignment == 0) {
+ goto end;
+ }
+ ptr = static_calloc_aligned(1, size, alignment);
+ *memptr = ptr;
+end:
+ return 0;
+}
+
+static
+void setup_static_allocator(void)
+{
+ assert(cur_alloc.calloc == NULL);
+ cur_alloc.calloc = static_calloc;
+ assert(cur_alloc.malloc == NULL);
+ cur_alloc.malloc = static_malloc;
+ assert(cur_alloc.free == NULL);
+ cur_alloc.free = static_free;
+ assert(cur_alloc.realloc == NULL);
+ cur_alloc.realloc = static_realloc;
+ assert(cur_alloc.memalign == NULL);
+ cur_alloc.memalign = static_memalign;
+ assert(cur_alloc.posix_memalign == NULL);
+ cur_alloc.posix_memalign = static_posix_memalign;
+}
+
+static
+void lookup_all_symbols(void)
+{
+ struct alloc_functions af;
+
+ /*
+ * Temporarily redirect allocation functions to
+ * static_calloc_aligned, and free function to static_free
+ * (no-op), until the dlsym lookup has completed.
+ */
+ setup_static_allocator();
+
+ /* Perform the actual lookups */
+ af.calloc = dlsym(RTLD_NEXT, "calloc");
+ af.malloc = dlsym(RTLD_NEXT, "malloc");
+ af.free = dlsym(RTLD_NEXT, "free");
+ af.realloc = dlsym(RTLD_NEXT, "realloc");
+ af.memalign = dlsym(RTLD_NEXT, "memalign");
+ af.posix_memalign = dlsym(RTLD_NEXT, "posix_memalign");
+
+ /* Populate the new allocator functions */
+ memcpy(&cur_alloc, &af, sizeof(cur_alloc));
}
void *malloc(size_t size)
{
- static void *(*plibc_malloc)(size_t size);
void *retval;
- if (plibc_malloc == NULL) {
- plibc_malloc = dlsym(RTLD_NEXT, "malloc");
- if (plibc_malloc == NULL) {
+ URCU_TLS(malloc_nesting)++;
+ if (cur_alloc.malloc == NULL) {
+ lookup_all_symbols();
+ if (cur_alloc.malloc == NULL) {
fprintf(stderr, "mallocwrap: unable to find malloc\n");
- return NULL;
+ abort();
}
}
- retval = plibc_malloc(size);
- tracepoint(ust_libc, malloc, size, retval);
+ retval = cur_alloc.malloc(size);
+ if (URCU_TLS(malloc_nesting) == 1) {
+ tracepoint(lttng_ust_libc, malloc,
+ size, retval, LTTNG_UST_CALLER_IP());
+ }
+ URCU_TLS(malloc_nesting)--;
return retval;
}
void free(void *ptr)
{
- static void (*plibc_free)(void *ptr);
-
- /* Check whether the memory was allocated with
- * static_calloc, in which case there is nothing
- * to free.
+ URCU_TLS(malloc_nesting)++;
+ /*
+ * Check whether the memory was allocated with
+ * static_calloc_align, in which case there is nothing to free.
*/
- if ((char *)ptr >= static_calloc_buf &&
- (char *)ptr < static_calloc_buf + STATIC_CALLOC_LEN) {
- return;
+ if (caa_unlikely((char *)ptr >= static_calloc_buf &&
+ (char *)ptr < static_calloc_buf + STATIC_CALLOC_LEN)) {
+ goto end;
}
- if (plibc_free == NULL) {
- plibc_free = dlsym(RTLD_NEXT, "free");
- if (plibc_free == NULL) {
+ if (URCU_TLS(malloc_nesting) == 1) {
+ tracepoint(lttng_ust_libc, free,
+ ptr, LTTNG_UST_CALLER_IP());
+ }
+
+ if (cur_alloc.free == NULL) {
+ lookup_all_symbols();
+ if (cur_alloc.free == NULL) {
fprintf(stderr, "mallocwrap: unable to find free\n");
- return;
+ abort();
}
}
- tracepoint(ust_libc, free, ptr);
- plibc_free(ptr);
+ cur_alloc.free(ptr);
+end:
+ URCU_TLS(malloc_nesting)--;
}
void *calloc(size_t nmemb, size_t size)
{
- static void *(*volatile plibc_calloc)(size_t nmemb, size_t size);
void *retval;
- if (plibc_calloc == NULL) {
- /*
- * Temporarily redirect to static_calloc,
- * until the dlsym lookup has completed.
- */
- plibc_calloc = static_calloc;
- plibc_calloc = dlsym(RTLD_NEXT, "calloc");
- if (plibc_calloc == NULL) {
+ URCU_TLS(malloc_nesting)++;
+ if (cur_alloc.calloc == NULL) {
+ lookup_all_symbols();
+ if (cur_alloc.calloc == NULL) {
fprintf(stderr, "callocwrap: unable to find calloc\n");
- return NULL;
+ abort();
}
}
- retval = plibc_calloc(nmemb, size);
- tracepoint(ust_libc, calloc, nmemb, size, retval);
+ retval = cur_alloc.calloc(nmemb, size);
+ if (URCU_TLS(malloc_nesting) == 1) {
+ tracepoint(lttng_ust_libc, calloc,
+ nmemb, size, retval, LTTNG_UST_CALLER_IP());
+ }
+ URCU_TLS(malloc_nesting)--;
return retval;
}
void *realloc(void *ptr, size_t size)
{
- static void *(*plibc_realloc)(void *ptr, size_t size);
void *retval;
- if (plibc_realloc == NULL) {
- plibc_realloc = dlsym(RTLD_NEXT, "realloc");
- if (plibc_realloc == NULL) {
+ URCU_TLS(malloc_nesting)++;
+ /*
+ * Check whether the memory was allocated with
+ * static_calloc_align, in which case there is nothing
+ * to free, and we need to copy the old data.
+ */
+ if (caa_unlikely((char *)ptr >= static_calloc_buf &&
+ (char *)ptr < static_calloc_buf + STATIC_CALLOC_LEN)) {
+ size_t *old_size;
+
+ old_size = (size_t *) ptr - 1;
+ if (cur_alloc.calloc == NULL) {
+ lookup_all_symbols();
+ if (cur_alloc.calloc == NULL) {
+ fprintf(stderr, "reallocwrap: unable to find calloc\n");
+ abort();
+ }
+ }
+ retval = cur_alloc.calloc(1, size);
+ if (retval) {
+ memcpy(retval, ptr, *old_size);
+ }
+ /*
+ * Mimick that a NULL pointer has been received, so
+ * memory allocation analysis based on the trace don't
+ * get confused by the address from the static
+ * allocator.
+ */
+ ptr = NULL;
+ goto end;
+ }
+
+ if (cur_alloc.realloc == NULL) {
+ lookup_all_symbols();
+ if (cur_alloc.realloc == NULL) {
fprintf(stderr, "reallocwrap: unable to find realloc\n");
- return NULL;
+ abort();
}
}
- retval = plibc_realloc(ptr, size);
- tracepoint(ust_libc, realloc, ptr, size, retval);
+ retval = cur_alloc.realloc(ptr, size);
+end:
+ if (URCU_TLS(malloc_nesting) == 1) {
+ tracepoint(lttng_ust_libc, realloc,
+ ptr, size, retval, LTTNG_UST_CALLER_IP());
+ }
+ URCU_TLS(malloc_nesting)--;
return retval;
}
void *memalign(size_t alignment, size_t size)
{
- static void *(*plibc_memalign)(size_t alignment, size_t size);
void *retval;
- if (plibc_memalign == NULL) {
- plibc_memalign = dlsym(RTLD_NEXT, "memalign");
- if (plibc_memalign == NULL) {
+ URCU_TLS(malloc_nesting)++;
+ if (cur_alloc.memalign == NULL) {
+ lookup_all_symbols();
+ if (cur_alloc.memalign == NULL) {
fprintf(stderr, "memalignwrap: unable to find memalign\n");
- return NULL;
+ abort();
}
}
- retval = plibc_memalign(alignment, size);
- tracepoint(ust_libc, memalign, alignment, size, retval);
+ retval = cur_alloc.memalign(alignment, size);
+ if (URCU_TLS(malloc_nesting) == 1) {
+ tracepoint(lttng_ust_libc, memalign,
+ alignment, size, retval,
+ LTTNG_UST_CALLER_IP());
+ }
+ URCU_TLS(malloc_nesting)--;
return retval;
}
int posix_memalign(void **memptr, size_t alignment, size_t size)
{
- static int(*plibc_posix_memalign)(void **memptr, size_t alignment, size_t size);
int retval;
- if (plibc_posix_memalign == NULL) {
- plibc_posix_memalign = dlsym(RTLD_NEXT, "posix_memalign");
- if (plibc_posix_memalign == NULL) {
+ URCU_TLS(malloc_nesting)++;
+ if (cur_alloc.posix_memalign == NULL) {
+ lookup_all_symbols();
+ if (cur_alloc.posix_memalign == NULL) {
fprintf(stderr, "posix_memalignwrap: unable to find posix_memalign\n");
- return ENOMEM;
+ abort();
}
}
- retval = plibc_posix_memalign(memptr, alignment, size);
- tracepoint(ust_libc, posix_memalign, *memptr, alignment, size, retval);
+ retval = cur_alloc.posix_memalign(memptr, alignment, size);
+ if (URCU_TLS(malloc_nesting) == 1) {
+ tracepoint(lttng_ust_libc, posix_memalign,
+ *memptr, alignment, size,
+ retval, LTTNG_UST_CALLER_IP());
+ }
+ URCU_TLS(malloc_nesting)--;
return retval;
}
+
+static
+void lttng_ust_fixup_malloc_nesting_tls(void)
+{
+ asm volatile ("" : : "m" (URCU_TLS(malloc_nesting)));
+}
+
+__attribute__((constructor))
+void lttng_ust_malloc_wrapper_init(void)
+{
+ /* Initialization already done */
+ if (cur_alloc.calloc) {
+ return;
+ }
+ lttng_ust_fixup_malloc_nesting_tls();
+ /*
+ * Ensure the allocator is in place before the process becomes
+ * multithreaded.
+ */
+ lookup_all_symbols();
+}
projects / lttng-ust.git / blobdiff